Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751110AbVLIMuJ (ORCPT ); Fri, 9 Dec 2005 07:50:09 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750884AbVLIMuJ (ORCPT ); Fri, 9 Dec 2005 07:50:09 -0500 Received: from fmr21.intel.com ([143.183.121.13]:51653 "EHLO scsfmr001.sc.intel.com") by vger.kernel.org with ESMTP id S1751110AbVLIMuH (ORCPT ); Fri, 9 Dec 2005 07:50:07 -0500 Date: Fri, 9 Dec 2005 04:49:39 -0800 From: Venkatesh Pallipadi To: Zwane Mwaikambo Cc: Venkatesh Pallipadi , linux-kernel , Linus Torvalds , Andrew Morton , Andi Kleen , Rohit Seth , Len Brown Subject: Re: [RFC][PATCH 2/3]i386,x86-64 Handle missing local APIC timer interrupts on C3 state Message-ID: <20051209044938.A26619@unix-os.sc.intel.com> References: <20051208181040.C32524@unix-os.sc.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: ; from zwane@arm.linux.org.uk on Fri, Dec 09, 2005 at 12:06:35AM -0800 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1358 Lines: 36 On Fri, Dec 09, 2005 at 12:06:35AM -0800, Zwane Mwaikambo wrote: > On Thu, 8 Dec 2005, Venkatesh Pallipadi wrote: > > > Whenever we see that a CPU is capable of C3 (during ACPI cstate init), we > > disable local APIC timer and switch to using a broadcast from external timer > > interrupt (IRQ 0). > > > > +void smp_send_timer_broadcast_ipi(struct pt_regs *regs); > > +void switch_APIC_timer_to_ipi(void *cpumask); > > +void switch_ipi_to_APIC_timer(void *cpumask); > > When is this used? +void smp_send_timer_broadcast_ipi(struct pt_regs *regs); This is called by the IRQ0 timer interrupt handler, to check whether any CPUs have enrolled for this broadcast. +void switch_APIC_timer_to_ipi(void *cpumask); Called by acpi processor driver when it find out that a particular CPU can support C3 state (and it is an Intel CPU). +void switch_ipi_to_APIC_timer(void *cpumask); Called by acpi processor driver again to reset to APIC_timer when C3 is not supported by the CPU. The acpi processor driver calls can be at the boot time, or can be at run time if BIOS enables/disables C3 at run time. Thanks, Venki - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/